September 11, 2007

So "smoke" is weather after all


Back in August I commented on Google's weather report, noting that it referred to Montana's forest fire smoke as "fog." Among other things, I wondered about the inventory of weather terms and whether "smoke" really qualifies as a category of fog. Or  whether it's really weather at all, for that matter. Sim Alberson, a meteorologist, now writes to clarify that there is indeed an international standard for weather terminology put out by the World Meteorological Organization, part of the United Nations. Be sure to check the link. It's very pretty.

Sure enough, "smoke" is included, along with 40 other different types of what Sim refers to as "frozen precipitation." You'll find "smoke" in box number 4 on the chart of accepted terms and symbols. So I guess it's official. "Smoke," "dust," (see boxes 6, 7, 8, 9, 30, 31, 32, 33, 34, and 35) and "sand" (see boxes 9, 30, 31, 32, 33. 34, and 35) are considered weather, at least by the WMO and the UN.

Now why meteororologists call this "frozen precipitation" remains unclear, at least to me. Maybe Sim can help explain this.

Update: John Maline informs me that the government also uses "smoke/haze" as one of its categories.

Posted by Roger Shuy at September 11, 2007 11:59 AM